转自：http://my.oschina.net/moks/blog/200344
【摘要】Because libv8 is the interface for the V8 engine used by therubyracer, you may need to use libv8, even if you have V8 installed already. If you wish to use your own V8 installation, rather than have it built for you, use the --with-system-v8 option.
G:gems>gem install libv8-3.11.8.17.gem -l
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
ERROR: Error installing libv8-3.11.8.17.gem:
ERROR: Failed to build gem native extension.
C:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb
creating Makefile
系统找不到指定的路径。
系统找不到指定的路径。
系统找不到指定的路径。
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.17/ext/libv8/builde
r.rb:49:in `setup_python!': libv8 requires python 2 to be installed in order to build
, but it is currently not available (RuntimeError)
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.17/ext
/libv8/builder.rb:35:in `block in build_libv8!'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.17/ext
/libv8/builder.rb:34:in `chdir'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.17/ext
/libv8/builder.rb:34:in `build_libv8!'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.17/ext
/libv8/location.rb:24:in `install!'
from extconf.rb:7:in `<main>'
Gem files will remain installed in C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/ge
ms/libv8-3.11.8.17 for inspection.
Results logged to C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/libv8-3.11.8.1
7/ext/libv8/gem_make.out
解决方案：
G:gems>gem install libv8-3.11.8.17.gem -- --with-system-v8
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
Successfully installed libv8-3.11.8.17
1 gem installed
Installing ri documentation for libv8-3.11.8.17...
Installing RDoc documentation for libv8-3.11.8.17...